1. Field of the Invention
The present invention generally relates to an automatic blood pressure measuring apparatus, and particularly to such an apparatus which displays temporary maximum blood pressure before displaying proper maximum blood pressure.
2. Discussion of the Prior Art
There is known an automatic blood pressure measuring apparatus including an inflatable cuff which is set around a body member of a subject, and means for detecting magnitudes of pulses (e.g., Korotkoff sounds) produced from the body member synchronously with heartbeat of the subject at each of continuous blood pressure measuring cycles, as pressure in the cuff is varied at each measuring cycle. The apparatus automatically determines a blood pressure of the subject based on the detected variation in magnitude of the heartbeat-synchronous pulses at each measuring cycle.
In the above apparatus, maximum and/or minimum blood pressure are/is not displayed until the pressure of the cuff is decreased from an upper predetermined level to a lower predetermined level at each measuring cycle, namely, magnitude variation of heartbeat-synchronous pulses is detected at each measuring cycle. However, maximum blood pressure is clinically important information. Thus, it is desirable that maximum blood pressure be earlier displayed as temporary maximum blood pressure than proper maximum blood pressure that is determined with higher accuracy based on the magnitude variation of the pulses detected at each measuring cycle and displayed at the end of the measuring cycle.
It has been proposed the art of determining temporary maximum blood pressure, in which a maximum difference in magnitude between each pair of consecutive two pulses is determined when pulses are consecutively detected at each measuring cycle and temporary maximum blood pressure is determined based on a magnitude of the pulse corresponding to the determined maximum difference. In this case, however, the maximum difference may be changed one after another as pulses are consecutively detected, whereby the temporary maximum blood pressure once determined and displayed may be replaced with another determined based on another maximum difference.